The present invention relates to a water transfer compound, a humidifier module, a humidifier as well as a device for the production of a water transfer compound. The water transfer compound can preferably be used for the humidification of process gases for fuel cells.
Fuel cells among others use gaseous process media, such as molecular hydrogen and oxygen for producing electrical current.
Such fuel cells usually use polymer-electrolyte membranes (PEM). During operation, such a PEM heats up to 80 or 90° C. It is important for the degree of efficiency of a fuel cell as well as for the durability of the PEM that relatively stationary conditions are given in the area of the PEM both with respect to temperature and humidity. In particular, drying-out of the PEM can have a negative impact on the durability and the degree of efficiency of the fuel cell.
For a purposeful setting of the degree of humidity of the process gases fed to the fuel cell, it is therefore usual to humidify particular process gases before they are fed to the fuel cell. To this end, humidifiers are known in which a water-permeable membrane is arranged between two flow plates comprising flow channels. This water-permeable membrane or water transfer layer separates a dry gas stream which is to be humidified on its one side and a gas stream which needs to be dehumidified on its other side.
As the water-permeable membrane, at least with a minimum humidification is essentially gas-tight, an approximation of the water content in both gases is achieved but a mixture of the gases themselves is prevented. It is however disadvantageous that known humidifiers are very expensive in their production and that tolerances for production and mounting have to be followed very closely in order to guarantee the desired humidity exchange.
Both components used to this end as they are used in the state of the art, in particular the water-permeable membrane, thus the water-transferring layer, are extremely thin and therefore limp, which causes a particular difficulty. If thermoplastic protective layers are used for the protection of these fragile membranes, their porosity impedes a grasping and positioning using the vacuum gripping systems usually used in automatized processes. Due to this, positioning procedures become very complex and even with the slightest imprecision leakages can occur, e.g. caused by folded or wrongly inserted membranes.